// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_CAST_RECEIVER_VIDEO_DECODER_H_
#define MEDIA_CAST_RECEIVER_VIDEO_DECODER_H_

#include <memory>

#include "base/callback.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "media/base/video_frame.h"
#include "media/cast/constants.h"
#include "media/cast/net/cast_transport_config.h"

namespace media {
namespace cast {

    class CastEnvironment;

    class VideoDecoder {
    public:
        // Callback passed to DecodeFrame, to deliver a decoded video frame from the
        // decoder.  |frame| can be NULL when errors occur.  |is_continuous| is
        // normally true, but will be false if the decoder has detected a frame skip
        // since the last decode operation; and the client might choose to take steps
        // to smooth/interpolate video discontinuities in this case.
        typedef base::Callback<void(const scoped_refptr<VideoFrame>& frame,
            bool is_continuous)>
            DecodeFrameCallback;

        VideoDecoder(const scoped_refptr<CastEnvironment>& cast_environment,
            Codec codec);
        virtual ~VideoDecoder();

        // Returns STATUS_INITIALIZED if the decoder was successfully constructed.  If
        // this method returns any other value, calls to DecodeFrame() will not
        // succeed.
        OperationalStatus InitializationResult() const;

        // Decode the payload in |encoded_frame| asynchronously.  |callback| will be
        // invoked on the CastEnvironment::MAIN thread with the result.
        //
        // In the normal case, |encoded_frame->frame_id| will be
        // monotonically-increasing by 1 for each successive call to this method.
        // When it is not, the decoder will assume one or more frames have been
        // dropped (e.g., due to packet loss), and will perform recovery actions.
        void DecodeFrame(std::unique_ptr<EncodedFrame> encoded_frame,
            const DecodeFrameCallback& callback);

    private:
        class FakeImpl;
        class ImplBase;
        class Vp8Impl;

        const scoped_refptr<CastEnvironment> cast_environment_;
        scoped_refptr<ImplBase> impl_;

        DISALLOW_COPY_AND_ASSIGN(VideoDecoder);
    };

} // namespace cast
} // namespace media

#endif // MEDIA_CAST_RECEIVER_VIDEO_DECODER_H_
